java - 组件运行时绘图

Question

所以，我的程序中有一个 keyListener。一旦激活，它就会在屏幕上绘制另一个组件。

发生的事情是最新的组件被绘制在屏幕上不应该或错误大小的地方(只是一瞬间)，然后捕捉到它指定的位置和大小，一切看起来都很棒。

有没有办法指示我的程序在将组件绘制到屏幕上之前计算组件的位置和大小以避免闪烁？

package core;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.InputEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Array;
import java.util.ArrayList;
import java.util.Locale;
import java.util.Properties;
import java.util.ResourceBundle;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.border.Border;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;



@SuppressWarnings("serial")
class DefaultFont extends Font
{
    public DefaultFont()
    {
        super("Arial", PLAIN, 20);
    }
}


@SuppressWarnings("serial")
class Page extends JPanel
{
    public JPanel largePage;
    public int content;

    public Page(JPanel panel, int index)
    {
        largePage = new JPanel();
        largePage.setLayout(new BoxLayout(largePage, BoxLayout.Y_AXIS));
        largePage.setMaximumSize(new Dimension(794, 1123));
        largePage.setPreferredSize(new Dimension(794, 1123));
        largePage.setAlignmentX(Component.CENTER_ALIGNMENT);
        largePage.setBackground(Color.WHITE);
        largePage.add(new Box.Filler(new Dimension(0, 96), new Dimension(0, 96), new Dimension(0, 96)));

        setMaximumSize(new Dimension(556, 931));
        setBackground(Color.LIGHT_GRAY);
        setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
        add(new Box.Filler(new Dimension(556, 0), new Dimension(556, 931), new Dimension(556, 931)));

        largePage.add(this);
        largePage.add(new Box.Filler(new Dimension(0, 96), new Dimension(0, 96), new Dimension(0, 96)));

        panel.add(largePage, index);
        panel.add(new Box.Filler(new Dimension(0, 40), new Dimension(0, 40), new Dimension(0, 40)));

        content = 0;

        Main.pages.add(this);
    }
}

@SuppressWarnings("serial")
class Heading extends JTextArea
{
    public boolean type;
    public AbstractDocument doc;
    public ArrayList<JPanel/*Question*/> questions;
    public ArrayList<JPanel/*List*/> list;  

    public Heading(boolean segment, Page page)
    {
        type = segment;

        setBackground(Color.RED);
        setFont(new Font("Arial", Font.BOLD, 20));

        Border in = BorderFactory.createDashedBorder(Color.BLACK);
        Border out = BorderFactory.createMatteBorder(0, 0, 10, 0, Color.WHITE);

        setBorder(BorderFactory.createCompoundBorder(out, in));
        setLineWrap(true);
        setWrapStyleWord(true);

        setText("Heading 1 Heading 1 Heading 1 Heading 1");

        doc = (AbstractDocument)this.getDocument();
        doc.setDocumentFilter(new DocumentFilter()
        {
            public void insertString(FilterBypass fb, int offs,String str, AttributeSet a) throws BadLocationException 
            {
                if ((fb.getDocument().getLength() + str.length()) <= 100)
                {
                    ;
                    fb.insertString(offs, str.replaceAll("\n", " "), a);
                }
                else
                {
                    int spaceLeft = 100 - fb.getDocument().getLength();
                    if (spaceLeft <= 0)
                        return;

                    fb.insertString(offs, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
                }
            }

            public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a) throws BadLocationException 
            {
                if (str.equals("\n"))
                { 
                    str = "";
                }
                if ((fb.getDocument().getLength() + str.length() - length) <= 100)
                {
                    fb.replace(offs, length, str.replaceAll("\n", " "), a);
                }
                else
                {
                    int spaceLeft = 100 - fb.getDocument().getLength() + length;
                    if (spaceLeft <= 0)
                        return;

                    fb.replace(offs, length, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
                }
            }
        });

        page.add(this, 0);
        page.content++;

        if (type)
        {
            questions = new ArrayList<JPanel>();
        }
        else
        {
            list = new ArrayList<JPanel>();
        }
    }
}

@SuppressWarnings("serial")
class Question extends JPanel
{
    public JPanel questionArea, numberArea, answerArea;
    public JLabel number;
    public JTextArea question;
    public AbstractDocument doc;

    public Question(Page page, int pageNum, int index)
    {
        setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
        setBorder(BorderFactory.createMatteBorder(0, 0, 5, 0, Color.WHITE));

        questionArea = new JPanel();
        questionArea.setLayout(new BoxLayout(questionArea, BoxLayout.X_AXIS));
        questionArea.setBorder(BorderFactory.createMatteBorder(0, 0, 8, 0, Color.WHITE));

        numberArea = new JPanel();
        numberArea.setLayout(new BorderLayout());
        numberArea.setBackground(Color.WHITE);

        number = new JLabel(pageNum+".  ", JLabel.RIGHT);
        number.setMinimumSize(new Dimension(100, 20));
        number.setPreferredSize(new Dimension(100, 20));
        number.setMaximumSize(new Dimension(100, 20));
        number.setFont(new Font("Arial", Font.PLAIN, 17));

        numberArea.add(number, BorderLayout.NORTH);

        questionArea.add(numberArea);

        question = new JTextArea();
        question.setFont(new Font("Arial", Font.PLAIN, 17));
        question.setBorder(BorderFactory.createDashedBorder(Color.BLACK));
        question.setLineWrap(true);
        question.setWrapStyleWord(true);
        question.setBackground(Color.GREEN);

        question.setText("Is this the first question?");

        doc = (AbstractDocument)question.getDocument();
        doc.setDocumentFilter(new DocumentFilter()
        {
            public void insertString(FilterBypass fb, int offs,String str, AttributeSet a) throws BadLocationException 
            {
                if ((fb.getDocument().getLength() + str.length()) <= 200)
                {
                    ;
                    fb.insertString(offs, str.replaceAll("\n", " "), a);
                }
                else
                {
                    int spaceLeft = 200 - fb.getDocument().getLength();
                    if (spaceLeft <= 0)
                        return;

                    fb.insertString(offs, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
                }
            }

            public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a) throws BadLocationException 
            {
                if (str.equals("\n"))
                { 
                    str = "";
                }
                if ((fb.getDocument().getLength() + str.length() - length) <= 200)
                {
                    fb.replace(offs, length, str.replaceAll("\n", " "), a);
                }
                else
                {
                    int spaceLeft = 200 - fb.getDocument().getLength() + length;
                    if (spaceLeft <= 0)
                        return;

                    fb.replace(offs, length, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
                }
            }
        });

        questionArea.add(question);

        add(questionArea);

        answerArea = new JPanel();
        answerArea.setLayout(new BoxLayout(answerArea, BoxLayout.Y_AXIS));

        add(answerArea);

        page.add(this, index);
        page.content++;
    }
}

@SuppressWarnings("serial")
class Answer extends JPanel
{
    public JPanel letterArea;
    public JLabel letter;
    public JTextArea answer;
    public char[] letters = {'a', 'b', 'c', 'd', 'e' };
    public AbstractDocument doc;

    public Answer(Question q, int index)
    {
        setLayout(new BoxLayout(this, BoxLayout.X_AXIS));


        letterArea = new JPanel();
        letterArea.setLayout(new BorderLayout());
        letterArea.setBackground(Color.WHITE);

        letter = new JLabel(letters[index-1]+")  ", JLabel.RIGHT);
        letter.setMinimumSize(new Dimension(150, 20));
        letter.setPreferredSize(new Dimension(150, 20));
        letter.setMaximumSize(new Dimension(150, 20));
        letter.setFont(new Font("Arial", Font.PLAIN, 17));

        letterArea.add(letter, BorderLayout.NORTH);

        add(letterArea);

        answer = new JTextArea();
        answer.setFont(new Font("Arial", Font.PLAIN, 17));

        Border in = BorderFactory.createDashedBorder(Color.BLACK);
        Border out = BorderFactory.createMatteBorder(0, 0, 5, 0, Color.WHITE);

        answer.setBorder(BorderFactory.createCompoundBorder(out, in));
        answer.setLineWrap(true);
        answer.setWrapStyleWord(true);

        answer.addKeyListener(new KeyListener()
        {
            @Override
            public void keyPressed(KeyEvent arg0)
            {
                new Answer((Question) ((JTextArea) arg0.getSource()).getParent().getParent().getParent(), 2);
                Main.mWindow.repaint();
                Main.mWindow.validate();
            }

            public void keyReleased(KeyEvent arg0) {}

            public void keyTyped(KeyEvent arg0) {}

        });

        doc = (AbstractDocument)answer.getDocument();
        doc.setDocumentFilter(new DocumentFilter()
        {
            public void insertString(FilterBypass fb, int offs,String str, AttributeSet a) throws BadLocationException 
            {
                if ((fb.getDocument().getLength() + str.length()) <= 200)
                {
                    ;
                    fb.insertString(offs, str.replaceAll("\n", " "), a);
                }
                else
                {
                    int spaceLeft = 200 - fb.getDocument().getLength();
                    if (spaceLeft <= 0)
                        return;

                    fb.insertString(offs, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
                }
            }

            public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a) throws BadLocationException 
            {
                if (str.equals("\n"))
                { 
                    str = "";
                }
                if ((fb.getDocument().getLength() + str.length() - length) <= 200)
                {
                    fb.replace(offs, length, str.replaceAll("\n", " "), a);
                }
                else
                {
                    int spaceLeft = 200 - fb.getDocument().getLength() + length;
                    if (spaceLeft <= 0)
                        return;

                    fb.replace(offs, length, str.substring(0,spaceLeft).replaceAll("\n", " "), a);
                }
            }
        });

        answer.setBackground(Color.PINK);
        add(answer);
        q.answerArea.add(this, index-1);
    }
}



public class Main
{

    public static Properties config;
    public static Locale currentLocale;
    public static ResourceBundle lang;

    public static JFrame mWindow;

    public static JMenuBar menu;
    public static JMenu menuFile, menuEdit;
    public static JMenuItem itmNew, itmClose, itmLoad, itmSave, itmSaveAs, itmExit, itmCut, itmCopy, itmPaste, itmProperties; 

    public static JDialog newDoc;
    public static JLabel newDocText1, newDocText2;
    public static JRadioButton questions, list;
    public static ButtonGroup newDocButtons;
    public static JButton newDocOk;
    public static Boolean firstSegment;

    public static JPanel workspace;
    public static JScrollPane scroll;
    public static ArrayList<Page> pages;


    public static void newDocumentForm()
    {
        //new document dialog
        mWindow.setEnabled(false);

        newDoc = new JDialog(mWindow, "newDoc");
        newDoc.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        newDoc.addWindowListener(new WindowListener ()
        {
            public void windowActivated(WindowEvent arg0) {}
            public void windowClosing(WindowEvent arg0)
            {
                mWindow.toFront();

                newDocText1 = null;
                newDocText2 = null;
                questions = null;
                list = null;
                newDocButtons = null;
                newDocOk = null;
                newDoc.dispose();

                mWindow.setEnabled(true);               
            }

            public void windowClosed(WindowEvent arg0) {}
            public void windowDeactivated(WindowEvent arg0) {}
            public void windowDeiconified(WindowEvent arg0) {}
            public void windowIconified(WindowEvent arg0) {}
            public void windowOpened(WindowEvent arg0) {}   
        });

        newDoc.setSize(400, 200);
        newDoc.setLocationRelativeTo(null);
        newDoc.setResizable(false);
        newDoc.setLayout(null);
        newDoc.setVisible(true);

        newDocText1 = new JLabel("newDocText1");
        newDocText1.setBounds(5, 0, 400, 20);

        newDocText2 = new JLabel("newDocText2");
        newDocText2.setBounds(5, 20, 400, 20);

        newDoc.add(newDocText1);
        newDoc.add(newDocText2);

        firstSegment = true;

        questions = new JRadioButton("questions");
        questions.setSelected(true);
        questions.setFocusPainted(false);
        questions.setBounds(10, 60, 400, 20);
        questions.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent arg0)
            {
                firstSegment = true;
            }
        });

        list = new JRadioButton("list");
        list.setFocusPainted(false);
        list.setBounds(10, 80, 400, 20);
        list.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent arg0)
            {
                firstSegment = false;
            }
        });

        newDoc.add(questions);
        newDoc.add(list);

        newDocButtons = new ButtonGroup();
        newDocButtons.add(questions);
        newDocButtons.add(list);

        newDocOk = new JButton("ok");
        newDocOk.addKeyListener(new KeyListener()
        {
            public void keyPressed(KeyEvent e)
            {
                if (e.getKeyCode() == KeyEvent.VK_ENTER)
                {
                    newDocOk.doClick();
                }
            }

            public void keyReleased(KeyEvent e) {}
            public void keyTyped(KeyEvent e) {}
        });

        newDocOk.setFocusPainted(false);
        newDocOk.setBounds(160, 120, 80, 40);
        newDocOk.setMnemonic(KeyEvent.VK_ACCEPT);
        newDocOk.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent arg0)
            {
                createNewDocument();
            }
        });

        newDoc.add(newDocOk);
        newDocOk.requestFocus();
    }

    public static void createNewDocument()
    {
        //dispose of new document dialog
        mWindow.toFront();

        newDocText1 = null;
        newDocText2 = null;
        questions = null;
        list = null;
        newDocButtons = null;
        newDocOk = null;
        newDoc.dispose();

        mWindow.setEnabled(true);

        //create document display               
        workspace = new JPanel();
        workspace.setLayout(new BoxLayout(workspace, BoxLayout.PAGE_AXIS));
        workspace.add(new Box.Filler(new Dimension(0, 40), new Dimension(0, 40), new Dimension(0, 40)));
        workspace.setBackground(Color.BLACK);

        scroll = new JScrollPane(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        scroll.getVerticalScrollBar().setUnitIncrement(20);
        scroll.setViewportView(workspace);

        pages = new ArrayList<Page>();

        Page p = new Page(workspace, 1);

        new Heading(true, p);

        Question q = new Question(p, 1, 1);

        new Answer(q, 1);

        mWindow.add(scroll, BorderLayout.CENTER);
        mWindow.repaint();
        mWindow.validate();

    }

    public static void main(String[] args) throws FileNotFoundException, IOException
    {   

        //create main window
        mWindow = new JFrame("title");
        mWindow.setSize(1000, 800);
        mWindow.setMinimumSize(new Dimension(1000, 800));
        mWindow.setLocationRelativeTo(null);
        mWindow.setLayout(new BorderLayout());
        mWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        mWindow.setVisible(true);

        //create menu bar
        menu = new JMenuBar();

        menuFile = new JMenu("file");
        menuEdit = new JMenu("edit");

        itmNew = new JMenuItem("new");
        itmNew.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N, ActionEvent.CTRL_MASK));
        itmNew.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                newDocumentForm();
            }
        });

        itmClose = new JMenuItem("close");
        itmClose.setActionCommand("Close");
        itmClose.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_W, ActionEvent.CTRL_MASK));

        itmLoad = new JMenuItem("load");
        itmLoad.setActionCommand("Load");
        itmLoad.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_L, ActionEvent.CTRL_MASK));

        itmSave = new JMenuItem("save");
        itmSave.setActionCommand("Save");
        itmSave.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, ActionEvent.CTRL_MASK));

        itmSaveAs = new JMenuItem("saveAs");
        itmSaveAs.setActionCommand("SaveAs");
        itmExit = new JMenuItem("exit");
        itmExit.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                //Add confirmation window!
                System.exit(0);
            }
        });


        itmCut = new JMenuItem("cut");
        itmCut.setActionCommand("Cut");
        itmCut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X, ActionEvent.CTRL_MASK));

        itmCopy = new JMenuItem("copy");
        itmCopy.setActionCommand("Copy");
        itmCopy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C, ActionEvent.CTRL_MASK));

        itmPaste = new JMenuItem("paste");
        itmPaste.setActionCommand("Paste");
        itmPaste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V, ActionEvent.CTRL_MASK));

        itmProperties = new JMenuItem("properties");
        itmProperties.setActionCommand("properties");
        itmProperties.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_P, ActionEvent.CTRL_MASK));

        menuFile.add(itmNew);
        menuFile.add(itmClose);
        menuFile.addSeparator();
        menuFile.add(itmLoad);
        menuFile.addSeparator();
        menuFile.add(itmSave);
        menuFile.add(itmSaveAs);
        menuFile.addSeparator();
        menuFile.add(itmExit);

        menuEdit.add(itmCut);
        menuEdit.add(itmCopy);
        menuEdit.add(itmPaste);
        menuEdit.addSeparator();
        menuEdit.add(itmProperties);

        menu.add(menuFile);
        menu.add(menuEdit);

        //create actionListener for menus



        mWindow.add(menu, BorderLayout.NORTH);

        mWindow.repaint();
        mWindow.validate();
    }
}

它不是 SSCCE(它是一整套相互依赖的组件，在新程序中复制它会让人头疼，甚至可能不会短很多)，但整个事情发生在 Answer 类中。您几乎可以忽略任何其他内容。

附言要绘制东西，请按 ctrl+n，然后输入!然后单击粉红色的文本区域，只需按一个按钮...

附言如果你按住那个按钮，你会得到非常酷的效果……:D

Answer 1

您可能需要在KeyListener 中validate() 和then repaint()。 Key bindings可能是更好的方法。